Series circuits of this kind, made up of a power semiconductor output stage and inductive load, are used for a variety of applications. The control signal always fully drives the power semiconductor output stage in order to minimize its power dissipation. When the power semiconductor output stage is disconnected, there occurs at the inductive load a disconnection energy W=½ LI2 that must be kept away from the power semiconductor output stage, since by way of the latter's parasitic diode the energy would generate a current flow that could result in overload or destruction of the power semiconductor output stage. To prevent this, the load is connected in parallel with a so-called freewheeling diode, which constitutes a power diode and must be matched to the switched power of the series circuit, and is therefore very expensive.
As described in International Patent Publication No. WO 96/09683, it is also known in the context of electronically commutatable motors to incorporate into the freewheeling circuit of an excitation winding the respective excitation winding that is to be energized next, and thereby already to achieve premagnetization. This system nevertheless still requires the freewheeling diode as a coupling diode between the excitation windings.